One benefit of swapping, at least in my experience, is longer times between needing to pay for hydro tests. The airgas I swap at is sure to give me a tank with the same or earlier date.

Earlier?

Oops, I mean later. Example: I give them a tank due August 2015 and I get a tank due January 2016. I don't think they dig through all of their tanks, most likely find the best tank on the outside edge of the pallet.

Just an fyi. Check your local suppliers before getting a 10lbs tank. Fills are never an issue, but when mine came up recertification, I could not find anyone actually willing to do the testing local. The best I got was an Airgas guy who definitely did not want my business ("you can bring it in and we'll ship it off to our testing center 100miles away and you *may* get it back if you're lucky").Everyone and their brother would do an on-site swap for a 5 or 20lbs tank. The 10lbs just seemed to be an uncommon size around here and no one other than Airgas even said they might recertify it. No one I found did swaps.

Just an fyi. Check your local suppliers before getting a 10lbs tank. Fills are never an issue, but when mine came up recertification, I could not find anyone actually willing to do the testing local. The best I got was an Airgas guy who definitely did not want my business ("you can bring it in and we'll ship it off to our testing center 100miles away and you *may* get it back if you're lucky").Everyone and their brother would do an on-site swap for a 5 or 20lbs tank. The 10lbs just seemed to be an uncommon size around here and no one other than Airgas even said they might recertify it. No one I found did swaps.

I found a guy here in Des Moines who only does CO2, mostly industrial and bulk beverage type work, who certified, stamped (Tar weight and full) and labeled a 2.5lb tank for me. He thought it was "stupid" (according to his office lady) but when I picked it up and explained what I was using it for for he decided it was a pretty good idea.

The swap only shops can be expected to limit your options but the small, hole in the wall, places can be very helpful.

I'm hoping the "May or may not get it back" comment meant your tank versus a comparable.

That's what I thought at first, but he didn't really reassure me anything would come back. Either way, I've moved to a smaller 5lbs tank now just so I can do easy swaps and not have to worry about it. I'm happy to pay a few bucks extra for the convenience of being able to do it at my LHBS.